The objective of this program is to improve treatment of leukemia. Serial studies of peripheral blood and bone marrow cells for leukemia associated antigens (LAAs), using sensitive primate and rabbit anti-human leukemia sera, will be performed following chemotherapy-induced bone marrow hypoplasia. Our intention is to distinguish between normal myeloblasts and leukemic cells and thus to prevent dangerous overtreatment. Immunodiagnosis will be used as a guide to institution or withholding of chemotherapy. The results of chemotherapy guided by immunodiagnosis will be compared to a historical control. In addition the antisera will be used to test peripheral blood cells of leukemia contacts (hematologists and relatives of leukemic patients). The blood of leukemia contacts will be tested for humoral and cellular immunity against leukemia. Patients having chronic granulocytic leukemia (CGL) will be randomized into a passive immunotherapy study after achieving complete remission (CR) defined as LAA-negative peripheral blood. Six CGL patients will receive chimpanzee anti-CGL serum and six CGL patients will receive no therapy. The effects of chimp serum on humoral and cellular immunity against leukemia, bone marrow and peripheral blood LAAs and duration of unmaintained CR will be determined. The effect of active immunotherapy using BCG and concentrated LAAs on duration of unmaintained CR of acute myelogenous leukemia (AML) will be studied. About 30 AML patients will be randomized when their peripheral blood and bone marrow are LAA-negative. The effects of active immunotherapy on humoral and cellular immunity against leukemia, duration of CR and survival will be determined.